Pass env variables to the compile step about buildstep

[holyjak]

I have looked little more into at and found out there is no ENV_DIR to pass on. The host machine has the file /home/dokku/<app name>/ENV with lines like export MY_VAR=something and the dokku script copies that into <container>/app/.profile.d/app-env.sh in the release phase - so the ENV is not available in the container during build/compile.

I guess that one way to "fix" this would be to propagate ENV to the container already before /build/builder is invoked and source it before executing builder or have builder sourcing it itself. The question is if we want to make all vars available at compile time (or only some of them).

Some background: Clojure code may contain macros that may be executed at compile time - and some macros may depend on the environment (f.ex. needing a path to a directory with template files).

[asm89]

@jakubholynet Are you using dokku? If yes one of these plugins might help you:
https://github.com/musicglue/dokku-user-env-compile
https://github.com/motin/dokku-user-env-compile

See: https://github.com/progrium/dokku/wiki/Plugins

[holyjak]

Thank you very much! Yes, I use Dokku. I will check out the plugins.

[holyjak]

Note: the Dokku plugins mirror the now deprecated Heroku lab feature user-env-compile, that has been replaced by the ENV_DIR argument as described on that page an in the Heroku Buildpack API.

It would be nice if Dokku replicated the change.

I'd accept a PR for it on dokku's side

[holyjak]

Great!
What would be a good implementation? I suppose that we want to keep the ENV file for backwards compatibility so enhancing dokku build to create /app/.env.d/ with a file for each env var based on parsing ENV would be likely a good solution?

[fmd]

Is there any chance we could then load these env vars into /exec? Any reason that wouldn't be a good idea?

[stuartpb]

@jakubholynet I don't know about putting it in /app - I think it would make more sense to put it in a top-level directory like /cache, which gets removed (as a volume or as part of the docker run command) immediately after building (and then not touching /app/.profile.d/app-env.sh).

Anyway, if you're putting it in, say, /env, then you could do something like this for Dokku without changing the ENV format:

docker run progrium/buildstep bash -c "
`sed 's/^export \([^=]\)=\(.*\)$/echo \2 > /env/\1/' <"$APP_DIR/ENV"`
/builder/build
# and, optionally
rm -rf /env"

[stuartpb]

Anyway, the way we're looking at doing this in plushu/plusku, it would be best if /build/builder looked for a /env directory, then called compile with it as a third parameter if it's present. (Alternately, it could just mkdir -p /env and let the buildpack freak out if nobody populated /env, which would probably be at least as smooth as the behavior when $3 is undefined.)

[progrium]

ENV_DIR for buildpacks is supported in the herokuish branch here. Can you try against that version?

[holyjak]

Nice. It is not easy for me anymore to try this out since I am away from the project where I experienced the problem but I will try to find the time to try to replicate it.

[progrium]

Thank you :)

[mjonuschat]

BTW, the ENV_DIR is also supported in the current buildstep image, no idea if dokku etc. are using it though..

[vincentfretin]

@yabawock Yes, Dokku supports ENV_DIR since dokku/dokku@7d5e0ba